<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
    .angel {
      position: absolute;
    }
  </style>
</head>
<body>
<img src="../../images/angel.gif" alt="" class="angel">
<script>
  var angel = document.querySelector('.angel');

  document.addEventListener('mousemove', function (e) {
    let x = e.pageX;
    let y = e.pageY;

    angel.style.left = x - 40 + 'px';
    angel.style.top = y - 50 + 'px';

    if (y <= 3) {
      angel.style.display = 'none';
    } else {
      angel.style.display = 'block';
    }
  })
</script>
</body>
</html>